Year % (national estimate) 1964 23.81 1973 28.29 1985 25.32 2001 47.21 2002 46.841 2003 47.779 2004 45.828 2005 42.661 2007 39.524 2008 39.223 2009 42.924 2010 42.678 2011 43.14 2012 44.282 2013 43.279 2014 42.707 2015 42.438 2016 42.108 2017 41.462 2018 40.021 2019 39.319 2020 39.27 2021 40.68 2022 37.278 2023 37.883